Smartphones are being used more and more for buying things using, for example, ApplePay™ and other systems. Smartphones are also getting more and more into biometrics, fingerprints, iris scans, and cryptography etc. A significant problem is that if someone loses their smartphone or it is stolen, the new possessor can substitute his/her biometrics for the original owner's biometrics and then clean them out of their money.
One solution to this problem is to store the biometric information on a remote site, but the thief can capture the owner's biometric data when it is sent to the remote site and then steal the device and input the captured data to spoof the system.
Other data may also need protection such as unique private keys of the owner which are stored on the device. If the device is stolen, then these private keys can also be stolen and used on other computing devices to allow access to information and assets which are intended only for the device owner. This permits the theft of cryptocurrency from digital wallets, for example.